I learned a lot from reading your comments!
KLM, you give scripture which states that angels do have
some sort of "covering", similar at least to a body. Although
they are often said to be spirit, and do not reproduce in
heaven. If they have some sort of "covering" which has
DNA capable of mixing with human DNA, then that would
be a way of producing Nephilim. But that would be distorting
their nature . They would have to go far
out of their own nature to commit this sin, probably further
than a human usually goes.
Also, I too have also seen a person who was like his
father, in personality, even though he did not know his father.
The ways in which he is like his father are his negative side,
and these must have come through DNA (in an unimaginable
maneuver) or through possibly a demon that was harbored
by each one.
Physical nature can produce personality traits--a person
with certain disease can be angry or weak or complaining;
a person who is cruel might be dealing with an excess or
lack of some body fluid, such as a hormone or enzyme.
Because we are so at the mercy of these physical problems
when they occur, we must depend on that pure grace which
Jesus offers to the imperfect. As KLM states in another post,
our redemption is not due to suffering in the tribulation but to
His grace, for not all who suffer will seek God. The Bible says
that some will curse God during the tribulation because of the
suffering of that time.
I have also seen, as you have, people change their nature
through accepting grace. They may still slide back into what
they were through DNA but they bounce back and ever seek